Sydney is 1-2 hours ahead of Osaka depending on the time of year. During Australian Eastern Daylight Time (AEDT, October-April), Sydney is 2 hours ahead. During Australian Eastern Standard Time (AEST, April-October), Sydney is 1 hour ahead.
Japan does not observe daylight saving time while Australia does, which causes the time difference to vary throughout the year. When it's 3:00 PM in Osaka, it's either 4:00 PM or 5:00 PM in Sydney.
Business hours align well! Standard business hours of 9:00 AM - 6:00 PM in Osaka correspond to 10:00 AM - 7:00 PM (or 11:00 AM - 8:00 PM during AEDT) in Sydney.
Osaka and Sydney are connected by direct flights of about 9.5 hours. Both cities are major Asia-Pacific economic centers with significant trade relationships between Japan and Australia.